This information sheet recommends powder metallurgy@ PM@ steel materials and metallurgical quality characteristics for use in specifying PM gearing. It identifies specifications and requirements for various PM steel materials for as--sintered@ through hardened or sinter hardened@ carburized case hardened@ and induction hardened gearing. Requirements are coded by process and class number@ the latter based on the density of the PM gear teeth. Characteristics covered include material composition@ density@ sinter processing (conventional@ high temperature and sinter hardening)@ secondary heat treatments and post heat treatment processing@ and their associated inspections.